Incidence of late radiation necrosis with transient mass effect after interstitial low dose rate radiotherapy for cerebral gliomas

Abstract

Late radiation necroses constitute a hazard in low dose rate interstitial irradiation for inoperable gliomas. An incidence of 40% (8/20 patients) was found after permanent implantation of Iodine-125 seeds. This finding may even underestimate the real frequency, because follow-up of unaffected patients was shorter than in patients with radiation necrosis. The necrotic reactions caused a transient mass effect, which lead to a significant deterioration of performance scores. Further manifestations of late delayed radiation damage were observed in two patients. The occurrence of radiation necrosis was correlated with total radiation dose, amount of implanted radioactivity, and with velocity of tumour shrinkage. A mechanism underlying the development of radiation necrosis is proposed: A rapid shrinkage of tumour after interstitial Iodine-125 implantation may cause a significant irradiation of surrounding brain tissue, which was initially lying outside the target volume. Since most patients affected by radiation necrosis were children or adolescents, the risk of radiation damage should be minimized. This could probably be achieved either by reduction of irradiation dose, or by using temporary implants of Iodine-125.

CT-Guided Interstitial HDR Brachytherapy for Recurrent Glioblastoma Multiforme

“…In LDR studies, this rate was up to 26% and even higher when BRT was combined with hyperthermia [5,9,22,43,50,52]. Symptomatic radionecrosis was diagnosed in two patients (2.5%), whereas in studies reporting results of [21,33,59]. Among our patients, we did not observe KPS, tumor volume or age to be significantly associated with improved survival after BRT.…”

Intra-operative radiation therapy for malignant brain tumours: Rationale, method, and treatment results of cerebral glioblastomas

“…Localized necrosis could, in a sense, confirm effective irradiation. In 40% of patients receiving brachytherapy, a kind of localized high dose irradiation, localized necrosis was reported14, 40 Gutin etal. 14 also noted longer survival in patients manifesting necrosis.…”

Local Targeting of Malignant Gliomas by the Diffusible Peptidic Vector 1,4,7,10-Tetraazacyclododecane-1-Glutaric Acid-4,7,10-Triacetic Acid-Substance P

“…Late radiation necrosis with mass effect and functional deterioration has frequently been observed following interstitial radiotherapy using 125 I seeds (45). In the neoadjuvant approach (i.e., targeted h-radiotherapy) followed by surgical debulking, induction of extensive radiation necrosis represents one of the goals of treatment.…”